A Request for Your Thoughts
An African python will sometimes forage actively for its food, but more often it will strike from ambush. Perhaps because it can detect potential prey by an animal’s heat-signature against a cooler background, P. natalensis eats almost exclusively warm-blooded vertebrates. During their hatchling-year, A.U.’s pythons probably subsist largely on mice, which abound in both density and species-variety. Maturing youngsters convert to rats, plus some rabbits and a few birds. Over the years we have examined the scat left by adult pythons: identifiable remains have included a few claws from small mammalian carnivores and many horns and hoofs from campus antelopes.
The maturation-rate of wild P. natalensis is not known. In captivity, kept warm and fed all it will eat, a healthy specimen can exceed 2.5m in length within the hatchling year. In the wild this does not happen, for
In other words, pythons hardly ever starve, so, although maturation can be quite slow, some pythons hang on, avoid the hazards of life for a few years, and eventually reach sexual maturity. Courtship and mating is well known for captive pythons, but these activities are seldom observed in the wild. Probably a patrolling male detects the special scent from the cloacal glands of a female;[4] he then follows her trail until he finds her, and mating occurs. Within about sixty days (???) after mating, the female will lay a whole bunch of eggs (perhaps as many as a hundred for a really big, well-fed momma). Most snakes abandon their eggs (or live-born young) immediately, but pythons are different. The female seeks a secluded spot (termite mound, mineshaft, whatever), lays her eggs, and coils her body around them. Then she initiates a series of contractions reminiscent of shivering in mammals. The metabolic heat produced by this intense muscular activity generates a great deal of heat, and, regardless of the ambient temperature, the eggs are maintained at about 30oC for the protracted incubation period (about 120 days). After the young do hatch,[5] the mother (apparently) loses all interest. And that is understandable; after all, she has endured a whole lot of very hard work throughout a very long fast, and she needs to go about the business of rebuilding her own resources (small antelope beware!).
We have some familiarity with pythons on the A.U. campus. In 2007 we have caught two pythons. The first was a 2m youngster in found in a molerat colony. As you can see from our photographs, this python was not at the peak of the species’ beauty. The cloudy eyes indicate that the animal is preparing to shed its skin, and the engorged ticks on its sides suggest that this snake had been spending a fair amount of time in mammal burrows. The second 2007 python was a freshly-shed sub-adult that we discovered one night about 50m behind our house.
Back in 2000 we had found another python—a bit smaller—and implanted a radio transmitter into the animal’s pleuroperitoneal cavity. This enabled us to keep up with the whereabouts of the snake for almost 100 days. Although our radio-python spent a considerable amount of time underground, in termite nests, it was also a real mover, sometimes covering over a kilometer in a single day. We were interested to note that the python used every major on-campus habitat-type (and it once ventured off campus, by about 10 meters), sometimes ambushing in a flooded lowland field, sometimes hunting in the mountain rocks. Movement between these areas required that the snake traverse a broad agricultural landscape; inevitably it made these crossings by crawling along a narrow, overgrown fence-line.
When I (Ab Abercrombie) talked proudly about my radio-python, folks around Old Mutare would always ask about its size, and they would disparage the entire telemetry enterprise when they learned that the animal was little longer than the height of a tall man. “Wait until you see the big one,” they would say; “it’s six meters long—a real python.” Somewhat sensitive about the dimensions of my favorite python, I would reply with equal scorn, “There’s no six-meter python around here. That’s almost record size, and nothing that big could survive in the agricultural heartland of Old Mutare.”
Then, in December of 2000, at the advent of the summer rains, I had trekked to the southeastern edge of campus to examine a mineshaft where I had previously photographed a pair of porcupines. The porkeys were not at home, and it was with some disappointment that I descended the mountain slope to ford the
[1] I write “
[2] Nowadays the big pythons of southern
[3] Except for the termite-eating scolecophidians, considered elsewhere, almost all snakes are adapted for taking large prey. Anatomically, the issue is, “how do you get big-diameter foodstuff into a small-diameter tube, when that tube has no equipment for slicing the foodstuff into pieces of convenient size?” In my herpetology course I talk at great (excessive?) length about swallowing-adaptations, which include stretchable skin, articulations of the quadrate bones, semi-independent lower jaws, and a flexible braincase. For now, let me say that, even among snakes, big pythons are real champions at swallowing really enormous stuff!
[4] Also in my herpetology course, I define snakes as creatures that live in a world of chemical information (loosely “smells”). In almost all snakes, special glands around the cloaca (the vent, where eliminatory and reproductive functions take place) produce substances with odors recognizable by other snakes. These are typically of high molecular weight and can therefore persist at detectable concentrations for a long time on the substrate where they have been deposited. Such chemical information is not apprehended by “smell” in the strict sense (sniffing through the nostrils that excites neural pathways interpreted by olfactory centers of the brain). Instead, the chemical messages from a snake’s cloacal glands are picked up on the tips of a snake’s tongue, with which the animal explores its environment. The tongue is withdrawn into the mouth, and its tips are inserted into a pair of openings in the roof of the mouth (the entrance to the vomero-nasal organ), from which the chemical information is relayed to the brain.
[5] In most python populations this occurs near the beginning of the summer rains, when food and thermal resources for the hatchlings are most readily available.